# tset 1

    tset(1)                                                         tset(1)

## NAME

           tset, reset - terminal initialization

## SYNOPSIS

           tset  [-IQVcqrsw] [-] [-e ch] [-i ch] [-k ch] [-m mapping]
           [terminal]
           reset [-IQVcqrsw] [-] [-e ch] [-i ch] [-k ch] [-m mapping]
           [terminal]

## DESCRIPTION

           Tset  initializes  terminals.   Tset  first determines the
           type of terminal that you are using.   This  determination
           is done as follows, using the first terminal type found.

           1. The terminal argument specified on the command line.

           2. The value of the TERM environmental variable.

           3.  (BSD  systems only.) The terminal type associated with
           the standard error output device in  the  /etc/ttys  file.
           (On Linux and System-V-like UNIXes, getty does this job by
           setting TERM  according  to  the  type  passed  to  it  by
           /etc/inittab.)

           4. The default terminal type, ``unknown''.

           If  the  terminal  type  was not specified on the command-
           line, the -m option mappings are  then  applied  (see  the
           section  TERMINAL  TYPE  MAPPING  for  more  information).
           Then, if the terminal type begins  with  a  question  mark
           (``?''), the user is prompted for confirmation of the ter-
           minal type.  An empty  response  confirms  the  type,  or,
           another  type  can be entered to specify a new type.  Once
           the terminal type has been determined, the terminfo  entry
           for  the  terminal  is retrieved.  If no terminfo entry is
           found for the type, the user is prompted for another  ter-
           minal type.

           Once  the  terminfo  entry  is retrieved, the window size,
           backspace, interrupt and line kill characters (among  many
           other things) are set and the terminal and tab initializa-
           tion strings  are  sent  to  the  standard  error  output.
           Finally,  if the erase, interrupt and line kill characters
           have changed, or are not  set  to  their  default  values,
           their  values  are displayed to the standard error output.
           Use the -c or -w option to select only the  window  sizing
           versus  the  other  initialization.   If neither option is
           given, both are assumed.

           When invoked as reset, tset sets cooked  and  echo  modes,
           turns  off cbreak and raw modes, turns on newline transla-
           tion and resets any  unset  special  characters  to  their
           default  values  before  doing the terminal initialization
           described above.  This is  useful  after  a  program  dies
           leaving  a  terminal  in an abnormal state.  Note, you may
           have to type

               <LF>reset<LF>

           (the line-feed character is normally control-J) to get the
           terminal to work, as carriage-return may no longer work in
           the abnormal state.  Also, the  terminal  will  often  not
           echo the command.

           The options are as follows:

           -c   Set  control  characters and modes.  -e Set the erase
                character to ch.

           -I   Do  not  send  the  terminal  or  tab  initialization
                strings to the terminal.

           -i   Set the interrupt character to ch.

           -k   Set the line kill character to ch.

           -m   Specify  a  mapping  from  a port type to a terminal.
                See the section TERMINAL TYPE MAPPING for more infor-
                mation.

           -Q   Do  not  display  any values for the erase, interrupt
                and line kill characters.  Normally tset displays the
                values  for  control characters which differ from the
                system's default values.

           -q   The terminal type is displayed to the  standard  out-
                put,  and the terminal is not initialized in any way.
                The option `-' by itself is equivalent but archaic.

           -r   Print the terminal type to the standard error output.

           -s   Print  the  sequence  of shell commands to initialize
                the environment variable TERM to the standard output.
                See  the section SETTING THE ENVIRONMENT for details.

           -V   reports the version of ncurses which was used in this
                program, and exits.

           -w   Resize  the  window  to  match  the  size deduced via
                setupterm.   Normally  this  has  no  effect,  unless
                setupterm is not able to detect the window size.

           The arguments for the -e, -i, and -k options may either be
           entered as actual characters or by using the  `hat'  nota-
           tion, i.e. control-h may be specified as ``^H'' or ``^h''.

## SETTING THE ENVIRONMENT

           It is often desirable  to  enter  the  terminal  type  and
           information  about  the  terminal's  capabilities into the
           shell's environment.  This is done using the -s option.

           When the -s option is specified, the commands to enter the
           information  into  the  shell's environment are written to
           the standard output.  If the SHELL environmental  variable
           ends in ``csh'', the commands are for csh, otherwise, they
           are for sh.  Note, the csh  commands  set  and  unset  the
           shell  variable  noglob,  leaving it unset.  The following
           line in the .login or .profile files will  initialize  the
           environment correctly:

               eval `tset -s options ... `

## TERMINAL TYPE MAPPING

           When the terminal is not hardwired into the system (or the
           current system information is incorrect) the terminal type
           derived  from the /etc/ttys file or the TERM environmental
           variable is often something generic like network,  dialup,
           or  unknown.   When tset is used in a startup script it is
           often desirable to provide information about the  type  of
           terminal used on such ports.

           The  purpose  of  the -m option is to map from some set of
           conditions to a terminal type, that is, to tell tset  ``If
           I'm  on this port at a particular speed, guess that I'm on
           that kind of terminal''.

           The argument to the -m option consists of an optional port
           type, an optional operator, an optional baud rate specifi-
           cation, an optional colon (``:'') character and a terminal
           type.   The port type is a string (delimited by either the
           operator or the colon character).  The operator may be any
           combination of ``>'', ``<'', ``@'', and ``!''; ``>'' means
           greater than, ``<'' means less than, ``@'' means equal  to
           and ``!'' inverts the sense of the test.  The baud rate is
           specified as a number and is compared with  the  speed  of
           the  standard  error  output  (which should be the control
           terminal).  The terminal type is a string.

           If the terminal type is not specified on the command line,
           the  -m mappings are applied to the terminal type.  If the
           port type and baud rate match the  mapping,  the  terminal
           type  specified  in the mapping replaces the current type.
           If more than one mapping is specified, the first  applica-
           ble mapping is used.

           For    example,    consider    the    following   mapping:
           dialup>9600:vt100.  The port type is dialup , the operator
           is  >, the baud rate specification is 9600, and the termi-
           nal type is vt100.  The result of this mapping is to spec-
           ify that if the terminal type is dialup, and the baud rate
           is greater than 9600 baud, a terminal type of  vt100  will
           be used.

           If no baud rate is specified, the terminal type will match
           any baud rate.  If no port type is specified, the terminal
           type   will   match   any  port  type.   For  example,  -m
           dialup:vt100  -m  :?xterm  will  cause  any  dialup  port,
           regardless of baud rate, to match the terminal type vt100,
           and any non-dialup port type to match  the  terminal  type
           ?xterm.   Note,  because of the leading question mark, the
           user will be queried on a default port as to whether  they
           are actually using an xterm terminal.

           No  whitespace  characters  are permitted in the -m option
           argument.  Also, to avoid problems  with  meta-characters,
           it  is  suggested  that  the  entire -m option argument be
           placed within single quote characters, and that csh  users
           insert  a  backslash character (``\'') before any exclama-
           tion marks (``!'').

## HISTORY

           The tset command appeared in BSD 3.0.  The ncurses  imple-
           mentation  was lightly adapted from the 4.4BSD sources for
           a terminfo environment by Eric S. Raymond <esr@snark.thyr-
           sus.com>.

## COMPATIBILITY

           The  tset  utility has been provided for backward-compati-
           bility with BSD environments (under  most  modern  UNIXes,
           /etc/inittab  and  getty(1) can set TERM appropriately for
           each dial-up line; this  obviates  what  was  tset's  most
           important  use).   This implementation behaves like 4.4BSD
           tset, with a few exceptions specified here.

           The -S option of BSD tset no longer works;  it  prints  an
           error message to stderr and dies.  The -s option only sets
           TERM, not TERMCAP.  Both these  changes  are  because  the
           TERMCAP  variable  is  no longer supported under terminfo-
           based ncurses, which makes tset -S useless (we made it die
           noisily rather than silently induce lossage).

           There  was  an  undocumented  4.4BSD feature that invoking
           tset via a link named `TSET` (or via any other name begin-
           ning  with  an  upper-case letter) set the terminal to use
           upper-case only.  This feature has been omitted.

           The -A, -E, -h, -u and -v options were  deleted  from  the
           tset  utility  in 4.4BSD.  None of them were documented in
           4.3BSD and all are of limited utility at  best.   The  -a,
           -d, and -p options are similarly not documented or useful,
           but were retained as they appear to be in widespread  use.
           It  is  strongly recommended that any usage of these three
           options be changed to use the -m option instead.   The  -n
           option  remains, but has no effect.  The -adnp options are
           therefore omitted from the usage summary above.

           It is still permissible to specify  the  -e,  -i,  and  -k
           options  without arguments, although it is strongly recom-
           mended that such usage be fixed to explicitly specify  the
           character.

           As  of  4.4BSD,  executing tset as reset no longer implies
           the -Q option.  Also, the interaction between the - option
           and the terminal argument in some historic implementations
           of tset has been removed.

## ENVIRONMENT

           The tset command uses these environment variables:

           SHELL
                tells tset whether to initialize TERM using sh or csh
                syntax.

           TERM Denotes  your  terminal  type.  Each terminal type is
                distinct, though many are similar.

           TERMCAP
                may denote the location of a termcap database.  If it
                is not an absolute pathname, e.g., begins with a `/',
                tset removes the variable from the environment before
                looking for the terminal description.

## FILES

           /etc/ttys
                system  port  name  to terminal type mapping database
                (BSD versions only).

           /usr/share/terminfo
                terminal capability database

## SEE ALSO

           csh(1), sh(1), stty(1),  curs_terminfo(3x),  tty(4),  ter-
           minfo(5), ttys(5), environ(7)

           This describes ncurses version 5.6 (patch 20081011).

                                                                    tset(1)